I pronounce it ress-ih-pross'-ih-tee, though when I'm talking fast it sounds more like ress-uh-pross'-uh-dee.
And when I'm drunk it sounds like rep-luh-soss'-uh-dee.
The pronunciation of the second syllable will probably depend on where you're from. 'ah' in some parts of the States, 'uh' in other parts, and I pronouce it with an 'i', because there's a fscking I in it (sorry, had to steal a joke from Eddie Izzard (50 seconds in))